Motor Vehicle Seat with Adjustable Seat Depth

ABSTRACT

A motor vehicle seat with a seat pan comprising a seat part and a supporting plate, said supporting plate being connected to the seat part via a guide for displacement in a longitudinal direction and comprising a front region forming the front edge of the seat pan. The supporting plate comprises a left and a right supporting wing. The left supporting wing forms the left front corner and the right supporting wing, the right front corner of the seat pan.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to German Applications DE 10 2007 003758.0, filed on Jan. 19, 2007 and DE 10 2007 049 863.4, filed on Oct.18, 2007, both of which are hereby incorporated by reference in theirentireties as part of the present disclosure.

BACKGROUND OF THE INVENTION

The invention relates to a seat pan of a motor vehicle seat. In someprior art motor vehicle seats, for example as shown in DE 196 28 381 A1,the supporting plate also forms the left front corner and the rightfront corner of the seat pan. The supporting plate is approximatelyT-shaped. If the supporting plate is moved forward, the legs of the Tmove away from the seat part and a gap forms, which increases as thesupporting plate is pushed further forward in the longitudinaldirection. This gap is a nuisance both visually and in practical use, itis difficult to conceal, a padding of the seat pan beneath this gap doesnot abut, it creates a noticeable hollow space. This is disadvantageous.

In the motor vehicle seats as shown in DE 698 27 303 T2, a front seatpart is adjusted relative to a rear seat part. The motor vehicle seat asshown in DE 199 13 503 A1 includes a seat pan that also has a fronttransverse piece and a rear transverse piece that may be spaceddifferent distances apart by means of an adjusting de-vice foradjustment of the seat depth. The invention disclosed herewith does notrelate to either of these types of motor vehicle seats.

In the motor vehicle seat as shown in DE 20 2004 020 657 U1, the entireseat part is displaced in the longitudinal direction relative to a seatback and the underframe of the seat. The effective length of the seatpan in the longitudinal direction remains the same. The invention is notconcerned with such type of motor vehicle seats either.

In view of the motor vehicle seat of the type mentioned herein above,the object of the invention is to improve the prior art motor vehicleseat in such a manner that a gap between the seat pan and the seat partdoes not appear as far as practicable, or at least that it is supportedas far as possible in order for it not to present a disadvantage andthat the thighs will not rest on a side edge of the supporting part.

Accordingly, it is an object of the present invention to overcome one ormore of the above-described drawbacks and disadvantages of the priorart.

SUMMARY OF THE INVENTION

The invention is directed to a motor vehicle seat with a seat pancomprising a seat part and a supporting plate, said supporting platebeing connected to the seat part via a guide for displacement in alongitudinal direction and comprising a front region forming the frontedge of the seat pan. The supporting plate comprises a left and a rightsupporting wing. The left supporting wing forms the left front corner ofthe seat pan and the right supporting wing forms the right front cornerof the seat pan.

In practical operation, the thighs of a passenger rest on the supportingplate. Depending on the thigh length of an individual passenger, thesupporting plate is pushed more or less forward in the longitudinaldirection. As a result, a passenger is given the opportunity to adjustthe seat to his or her own size, thus achieving the result that thethighs rest on the seat pan up to near the knee, and that they do notundesirably protrude freely too far forward without being supported bythe seat front edge. Generally, the supporting plate does not laterallysupport the thighs, lateral hold being normally provided by the seatpart.

The seat pan has a padding that also covers the supporting plate andalso an external covering. Padding and covering have a certainelasticity, which however is by far not sufficient to cover all therelative positions between seat part and supporting plate withoutcovering and padding making relative movements.

The padding is supported in the region of the left front corner and ofthe right front corner of the seat by the two supporting wings. Usually,the padding is configured to be a foam body. The padding retains itscontours and does not collapse.

When an adjustment is being made, there is a relative movement betweenthe supporting wings and the seat part. In order to facilitate thismovement, and in particular also to avoid any noise, gliding means arepreferably provided between the free end of each supporting wing and theseat part.

At their free end, the supporting wings can rest laterally on the seatpart, they may however also engage into openings provided on the seatpart.

The supporting plate is adjustable in the longitudinal direction withrespect to the seat part by means of suited adjustment devices which maybe configured to be motor- or hand-driven.

The supporting wings may be connected directly to the supporting plate,they may however also be hinged thereto. In case they are hingedthereto, the joint axis extends substantially perpendicular to the seatsurface. The supporting wings always abut the seat part at their freeend.

In the longitudinal direction, the supporting plate has a size that isshorter than half the corresponding length dimension of the seat part.It is approximately 30 to 45%. Behind the supporting plate a quite longarea is kept free, said area being usually tensioned by springs andserving to receive a passenger's buttocks.

The supporting plate is approximately 25 to 40 cm wide. In oneembodiment, the supporting plate is 30 cm wide.

In an advantageous development, the invention suggests fixing thepadding to the seat part but not to the supporting plate. The paddingassumes different positions with respect to the supporting plate,depending on the length adjustment of the supporting plate. The coveringmoves together with the padding. As usual, the covering ends underneaththe seat pan, its borders are concealed when viewed from a normal angle.Depending on the adjustment of the supporting plate relative to the seatpart, the position of the covering border changes. In the region of thesupporting plate, the covering is elastically connected to thesup-porting plate or elastically retained. In the first case, springsare provided for ex-ample, said springs being interposed between thesupporting plate (or supporting part) and the border of the covering. Inthe second case, a rubber band or a similar elastic means is sewn intothe edge of the covering for example. Advantageously, the padding has aslide coating on its underside in order to facilitate the relativemovement between the padding and the supporting plate. Depending on theadjustment of the supporting plate, the front upper seat edge of theseat pan is formed by a different portion of the covering. This edge,which is particularly subjected to wear, changes its position on thecovering so that different portions of the covering are subjected towear and strain.

Other advantages of the present invention and/or of the currentlypreferred embodiments thereof will become more readily apparent in viewof the following detailed description of the currently preferredembodiments and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: is a perspective view of a first embodiment of a motor vehicleseat with adjustable seat depth in accordance with the invention;

FIG. 2: is a top view of the seat pan of the motor vehicle seat as shownin FIG. 1, with padding and covering removed;

FIG. 3: is a cross section in the x-z plane through the center of theseat pan in the retracted position (continuous line) and in the advancedposition (dash-dot line) of the supporting plate;

FIG. 4: is a perspective view of the seat pan, the covering is drawn ina dash-dot line;

FIG. 5: is a perspective representation like in FIG. 4 for a secondexemplary embodiment; and

FIG. 6: is a perspective representation like in FIG. 4 for a thirdexemplary embodiment.

DETAILED DESCRIPTION

The motor vehicle seat includes a seat pan 20, a seat back 22 and anunderframe 24. The seat pan 20 and the seat back 22 are provided with acovering 26, made for example from fabric or leather. Beneath thiscovering 26, there is a padding 28, as shown in FIG. 3.

The mechanical and carrying structure of the seat pan 20 has a seat part30 and a supporting plate 32. Both are displaceable with respect to eachother in a longitudinal direction via a guide 34; the FIGS. 1 through 3show the two extreme positions by way of example, the position with theshortest seat length being shown in a continuous line and the positionwith the greatest seat length in a dash-dot or dashed line. In the ydirection, the supporting plate 32 has a width that only is about 60% ofthe width of the seat part 30, measured in the same direction. In theposition with the shortest seat length, the supporting plate 32 isalmost completely located in a recess of the seat part 30 that is opentoward the front, meaning in the x direction. On the side of thisrecess, meaning when viewed in the y direction, the seat part 30 has aleft and a right seat part 38 the upper side of which is located higherthan the supporting plate 32 in the z direction. These side parts 38serve to laterally hold the thighs of a user. The thighs of a user reston the supporting plate 32, which is configured to be large enough forthis purpose.

In the position in which the supporting plate 32 projects farthest inthe x direction said supporting plate projects significantly forwardwith respect to the seat part 30. On the left and right side of thesupporting plate 32, there are cavities 40. The supporting plate 32 hasa front region 42 that forms the front edge of the mechanical structureof the seat part. On each of its extreme regions located in the ydirection, there is disposed a supporting wing 44. In the firstembodiment, shown in FIGS. 1 through 4, it is respectively hinged abouta pivot axis 45 that extends substantially parallel to the z axis. It iselastically biased by a spring (not shown) or another elastic means insuch a manner that a free end 46 of the respective supporting wing 44 isbiased toward the supporting plate 32 or, put another way, toward theguide 34. It fits against a slide or guide surface 49 on the seat part30. The left supporting wing 44 forms the left front corner of the seatpart 20, the right supporting wing 44, the right front corner of theseat part. In the position in which the seat has the shortest length,the supporting wings 44 fit against the outer surfaces of the side parts38, leaving but a small space. In the position in which the supportingplate 32 is pushed farthest forward, there is a large space and thesupporting wings 44 project slightly further in the x direction than inthe case in which the seat has the shortest length.

Substantially, the supporting wings 44 form the foremost side edges ofthe seat pan 20. They have a profile height of at least 30 mm in the zdirection, and substantially a C profile. In one embodiment, they have aprofile height of at least 50 mm in the z direction. They can absorbforces in the z direction as they occur in normal operation.

The free ends 46 fit slidingly against the sides of the seat part 30.Preferably, a slide means 48, for example a plastic layer, is providedat the free ends. The free ends 46 show substantially backward in thelongitudinal direction 36.

The seat pan 20 has a spring system 50 that bridges a recess in the seatpart 30. A hand or motor driven adjustment device 51 is associated withthe guide 34, reference being made here to the manual adjustment deviceaccording to DE 296 23 565 U1. A motor-driven adjustment device isdisclosed in the patent application filed the same day by the applicant“Motor Vehicle seat with Adjustable Seat Depth,” which is fullyincorporated herein by reference.

As shown in FIG. 3, a slide surface 52 is interposed between thesupporting plate 32 and the padding 28. It is provided either on thesupporting plate 32 or, as shown in FIG. 3, on the padding 28. It ismade from a plastic foil, for example. It covers the surface of thepadding 28 in the region that is in contact with the supporting plate 32and with its supporting wings 44. Upon adjustment of the supportingplate 32 relative to the seat part 30, the supporting plate 32 movesrelative to the padding 28. The slide surface 52 facilitates thisrelative movement. In the region of the front edge of the seat, thepadding 28 is not connected with the mechanical carrier structure. Anelastic part 54, for example a rubber band, is sewn in the border of thecovering 26. Alternatively, the border is connected to the mechanicalcarrier structure through springs, rubber strips or the like. As aresult, the border is allowed to move relative to the supporting plate32. Upon adjustment of the seat depth, the edge of the covering 26 isdisplaced, although it always remains beneath the seat pan. As a result,other areas of the covering form the foremost upper padding edge,depending on the position of the supporting plate 32. In the regionlocated behind the supporting plate 32, in particular in the region ofthe spring system 50, the padding 28 is connected, according to priorart, to the seat part 30 and so on, since there is no relative movementin this region. The limit between normal covering and movable coveringis approximately in a line parallel to the y axis that passes throughthe basis of the U-shaped recess of the seat part 30. It is alsopossible to connect the side parts 38 to the padding 28.

The seat part 30 may also be configured differently from theconfiguration shown. It is illustrated as a cushion shell, but may alsobe configured to be a half shell or a simple front crossbeam.

In another embodiment, as shown in, FIG. 5, the supporting wings 44 arerealized by U-shaped parts made from a metal or a plastic tube. The freeends of the legs are connected to the supporting plate 32. The legs areresilient and fit against the seat part 30 thanks to their intrinsicelasticity.

In the embodiment shown in FIG. 6, the supporting wings 44 are made fromtwo bars each, said bars being also fixed to the supporting plate 32. Attheir free ends, they engage openings 56 that are provided in the seatpart 30 for this purpose. Upon adjustment, there is a relative movementbetween each opening 56 and the bars forming the supporting wings 44.

1. A motor vehicle seat with a seat pan comprising: a seat part and asupporting plate, said supporting plate being connected to the seat partvia a guide for displacement in a longitudinal direction and comprisinga front region forming the front edge of the seat pan, wherein saidsupporting plate comprises a left and a right supporting wing and theleft supporting wing forms the left front corner and the rightsupporting wing forms the right front corner of the seat pan.
 2. Themotor vehicle seat as defined in claim 1, wherein the supporting wingsare connected either to the supporting plate in a respective pivot jointor directly to the supporting plate.
 3. The motor vehicle seat asdefined in claim 1, wherein the supporting wings are configured to beelastic.
 4. The motor vehicle seat as defined in claim 1, wherein a handor motor driven adjustment device for adjustment in the longitudinaldirection is provided between the seat part and the supporting plate. 5.The motor vehicle seat as defined in claim 1, wherein the supportingwings have a free end and that said free end fits laterally against theseat part, a slide means being provided between the free end and theseat part.
 6. The motor vehicle seat as defined in claim 1, wherein eachsupporting wing has a free end and that said free end substantiallypoints backward in the longitudinal direction.
 7. The motor vehicle seatas defined in claim 1, wherein the seat part comprises left and rightlateral slide surfaces or guide surfaces for abutment of the respectiveone of the supporting wings.
 8. The motor vehicle seat as defined inclaim 1, wherein the seat part comprises two openings and that onesupporting wing engages in each opening.
 9. The motor vehicle seat asdefined in claim 1, wherein the seat part has a seat part width and thesupporting plate has a width that is maximally about 80% of the seatpart width.
 10. The motor vehicle seat as defined in claim 1, whereinthe seat pan includes a padding a portion of which is located above thesupporting plate and that, upon adjustment of the supporting plate inthe longitudinal direction, the supporting plate moves together with itssupporting wings relative to the padding.
 11. The motor vehicle seat asdefined in claim 9, wherein the padding comprises a slide surface on itsunderside turned toward the supporting plate.
 12. The motor vehicle seatas defined in claim 9, wherein the seat pan further comprises a coveringthat is located outside of the padding that it covers and has an endregion that is located underneath the supporting plate, wherein the endregion is elastically retained and is not directly connected to thesupporting plate.
 13. The motor vehicle seat as defined in claim 10,wherein the seat pan further comprises a covering that is locatedoutside of the padding that it covers and has an end region that islocated underneath the supporting plate, wherein this end region iselastically retained and is not directly connected to the supportingplate.
 14. The motor vehicle seat as defined in claim 12, wherein theend region comprises an elastic part.
 15. The motor vehicle seat asdefined in claim 13, wherein the end region comprises an elastic part.16. The motor vehicle seat as defined in claim 1, wherein the supportingplate comprises a first insertion opening on one seat side and the seatpart has a mating second plug-type projection on this seat side or thesupporting plate comprises a first plug-type projection on one seat sideand the seat part has a mating second insertion opening on this seatside.